The ongoing debate about what models of cervical dilatation and fetal descent should guide clinical decision-making has sown uncertainty among obstetric practitioners. We previously argued that the adoption of recently published labor assessment guidelines promoted by the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine may have been premature. Before accepting any new clinical approaches as the standard of care, their underlying hypotheses should be thoroughly tested to ensure they are at least equivalent (or, preferably, superior) to existing management paradigms. Some of the apparent urgency to subscribe to new clinical tactics has been fueled by legitimate concerns about the rise in the cesarean delivery rate over the past several decades. A major contributor to this change in practice patterns is that more cesarean deliveries are being done for diagnoses that fall under the rubric of dystocia than ever before. As a consequence, traditional labor curves-fundamental for assessing labor progress-and the practice paradigms associated with them have received intense scrutiny as a possible contributor to this delivery trend. Moreover, the recent proposal of new labor curves and accompanying management guidelines has, understandably, fed the appetite to correct a perceived problem. However, the cesarean delivery rate rose most rapidly during decades when there was no major change in traditional labor curves or in the guidelines for their interpretation. Also, during the years since the new guidelines were first published, there has been no major fall in cesarean delivery frequency. This raises the question of whether there was truly a fundamental flaw in the traditional labor management paradigms or whether their proper interpretation and use had been somehow forgotten, ignored, or corrupted. More important, existing studies have shown that application of the new guidelines often (but not always) results in a modest fall in the cesarean delivery rate, but that this change may be accompanied by significant increases in maternal and neonatal morbidity. These results strongly suggest more caution in the adoption of the American College of Obstetricians and Gynecologists / Society for Maternal-Fetal Medicine labor assessment recommendations. They are based on a hypothesis that has yet to undergo thorough evaluation of its risks and benefits.

In a recent review we expressed concerns about new guidelines for the assessment and management of labor recommended jointly by the American Congress of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM). These guidelines are based heavily on a new concept of how cervical dilatation and fetal descent progress, derived from the work of Zhang et al. In their Viewpoint article they have addressed, but not allayed, the concerns we described in our review. We assert that the dilatation curve promulgated by Zhang et al cannot be reconciled with direct clinical observation. Even if they were correct, however, it still does not follow that the ACOG/SMFM guidelines should recommend replacing the coherent system of identifying and managing labor aberrations described by Friedman. That system is grounded in well-established clinical principles based on decades of use and the objectively documented association of some labor abnormalities with poor fetal and maternal outcomes. Recommendations for new clinical management protocols should require the demonstration of superior outcomes through extensive, preferably prospective, assessment. Using untested guidelines for the management of labor may adversely affect women and children. Even if those guidelines were to reduce the currently excessive cesarean delivery rate, the price of that benefit is likely to be a trade-off in harm to parturients and their offspring. The nature and degree of that harm needs to be documented before considering adoption of the guidelines.